In optical communications technology, optical demultiplex equipment with dispersion gratings has proved successful in systems which are used to simultaneously process a large number of light signals of different wave length. The most favourable features of dispersion gratings is their relatively small overall size and their relatively low insertion damping of each transmission channel.
A considerable problem arises in the use of dispersive grating demultiplex equipment relates to the channel separation. In currently known wavelength multiplex equipment, the wave length difference between adjacent channels, in other words the channel spacing, is fixed at a specific value, for example 30 nm. As a consequence of this, taking into account the geometry which is preset by the construction of the dispersion grating, there must be a specific arrangement of the light conductor fibers intended for decoupling of the individual channels.